U.S. Army units in Japan began a weeklong drill Monday on emergency medical operations at a military site in the city of Sagamihara, Kanagawa Prefecture.

The Medex 2000 exercise, being staged on a mock battlefield at Sagami Grand Depot, is the first full-scale U.S. military drill on emergency medical operations to be held in Japan, excluding one held during the Vietnam War. It is scheduled to end Saturday.

Locals, who have long known the depot as a supply storage facility, are voicing concerns over its new function. The city of Sagamihara called earlier this month for the drill's cancellation.

According to U.S. Army officials stationed in the prefecture's Camp Zama, about 700 U.S. service members, those from the navy and air force in Japan as well as some officers and medical staff based in South Korea, are to participate in the drill.

As part of the drill, helicopters will transport soldiers acting as patients to a field hospital set up using warehouses on the depot.

The exercise will also include practicing treatment for injuries inflicted by chemical weapons.

The hospital is equipped with 500 beds, surgery rooms, X-ray facilities and an intensive care unit.

U.S. Army officials said the exercise was not related to U.S.-Japan defense cooperation guidelines for emergencies in areas surrounding Japan.

City assembly members, including Tokio Kaneko, who has been actively involved in opposing the local U.S. military presence and monitoring depot activities, warned that the storage facility is slowly shifting into a training camp.

Kaneko and others were planning to hold a protest rally Monday evening at a park near the facility.

The U.S. Army has invited the city mayor, members of the city assembly and others to the exercises, which will be open to the media.